1. Field of the Invention
This invention relates generally to a system and method for monitoring the health of electrical components on a vehicle and, more particularly, to a system and method for monitoring the health of electronic components on a vehicle where sensors and other electrical devices detect abnormal environmental conditions and send information concerning the detection through a hierarchical structure to a high level controller.
2. Discussion of the Related Art
Diagnostics monitoring of various vehicle systems is an important vehicle design consideration so as to be able to quickly detect system faults, and isolate the faults for maintenance and service purposes. These vehicle systems typically employ various sub-systems, actuators and sensors, such as yaw rate sensors, lateral acceleration sensors, steering hand-wheel angle sensors, etc., that are used to help provide control of the vehicle. If any of the sensors, actuators and sub-systems associated with these systems fail, it is desirable to quickly detect the fault and activate fail-safe (fail-silent or fail-operational) strategies so as to prevent the system from improperly responding to a perceived, but false condition. It is also desirable to isolate the defective sensor, actuator or sub-system for maintenance, service and replacement purposes. Thus, it is necessary to monitor the various sensors, actuators and sub-systems employed in these systems to identify a failure.
It is a design challenge to identify the root cause of a fault and isolate the fault all the way down to the component level, or even the sub-system level, in a vehicle system. The various sub-systems and components in a vehicle system, such as a vehicle brake system or a vehicle steering system, are typically not designed by the vehicle manufacturer, but are provided by an outside source. Because of this, these components and sub-systems may not have knowledge of what other sub-systems or components are doing in the overall vehicle system, but will only know how their particular sub-system or component is operating. Thus, these outside sub-systems or components may know that they are not operating properly, but MAY not know if their component or sub-system is faulty or another sub-system or component is faulty. For example, a vehicle may be pulling in one direction, which may be the result of a brake problem or a steering problem. However, because the brake system and the steering system do not know whether the other is operating properly, the overall vehicle system may not be able to identify the root cause of that problem.
Each individual sub-system or component may issue a diagnostic trouble code indicating a problem when they are not operating properly, but this trouble code may not be a result of a problem with the sub-system or component issuing the code. In other words, the diagnostic code may be set because the sub-system or component is not operating properly, but that operation may be the result of another sub-system or component not operating properly.
Diagnostic and prognostic techniques for vehicle state of health monitoring can help forecast the occurrence of a problem in order to take preventive measures before significant loss of functionality has occurred or before damage is done. These techniques become more important for systems where the failure of the system can have critical implications for the overall system. Further, system manufacturers can help prevent their customers from being dissatisfied due to the failure of various systems by using diagnostic and prognostic techniques.
Health monitoring of vehicle components, devices and electrical systems can extend down to the chip level where electrical devices may be able to detect the occurrence of an abnormal situation, such as a high voltage spike. Generally, this information is not transmitted to other system devices and components that might benefit from such information.
A variety of environmental events are known to weaken, damage, or otherwise shorten the useful life of electronic components. For example, excessive temperatures, voltage spikes, impacts or vibration, excessive pressure, etc. are potential problems.